I remember when I was living in Rio. In winter, I used to wear two long sleeves t-shirts and get quite surprised when the temperature was around 18°C. Now, I am wearing a sleeveless t-shirt and it's alright. It's raining like hell. Just because now I have decided to walk from the train station to work (and vice-versa), the rain won't stop. It doesn't matter, I'm Brazilian and I never give up! By the way, the walk is about 20-25 minutes each way. Not too bad.